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Error code reference

Samsung Air Conditioner Error Code P402

High temperature of COND sensor

Samsung codesSamsung air conditioner codes

High temperature of COND sensor – condensate temperature of compressor reaches 67°C; system down on 6th detection.

First step from the service manual

Check for obstacles at the air inlet/outlet of outdoor unit.

The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.

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What P402 means on a Samsung air conditioner

Error code P402 on a Samsung air conditioner indicates that the condensate temperature sensor on the compressor has detected an excessively high temperature, specifically reaching or exceeding 67°C. This sensor monitors the temperature at the condensing side of the compressor, which reflects how effectively the outdoor unit is rejecting heat. When this threshold is crossed, the system logs a detection event. After the sixth consecutive or cumulative detection of this condition, the system initiates a full shutdown to prevent compressor damage.

The root cause of P402 is almost always insufficient heat dissipation at the outdoor unit. The condenser coil and compressor rely on adequate airflow to release heat from the refrigerant cycle. When airflow is restricted by debris, vegetation, a recessed installation, or a dirty coil, heat builds up rapidly and drives the condensate temperature past the 67°C limit. Ambient temperature extremes can contribute, but physical airflow obstruction is the most common trigger.

Because the system only shuts down on the sixth detection, earlier occurrences may go unnoticed while the unit continues operating in a degraded thermal state. This repeated thermal stress accelerates compressor wear. Technicians should treat P402 as a serious protection event, not simply a sensor fault, and focus the initial investigation on the outdoor unit's airflow path, coil cleanliness, and installation clearances before suspecting refrigerant charge or sensor failure.

Source: manufacturer service documentation.

Common causes of P402

  1. 01

    Blocked air inlet or outlet on outdoor unit

    Wiring / connection

    Debris, vegetation, fencing, or stored items placed too close to the outdoor unit restrict the airflow needed to dissipate heat from the condenser. Inspect all four sides and the top of the unit for obstructions and verify that minimum clearance distances are maintained.

  2. 02

    Dirty or fouled condenser coil

    Wiring / connection

    Dirt, dust, cottonwood, or grease buildup on the condenser coil fins significantly reduces heat transfer efficiency, causing compressor discharge temperatures to climb. Inspect the coil fins and clean them with a coil cleaner and low-pressure rinse if fouling is present.

  3. 03

    Refrigerant charge issue

    Part replacement

    An incorrect refrigerant charge, either overcharge or undercharge, disrupts the normal condensing cycle and can elevate compressor and condensate temperatures beyond normal limits. A manifold gauge set is required to evaluate system pressures and confirm proper charge.

  4. 04

    Condenser fan motor or blade failure

    Part replacement

    If the condenser fan motor is running slowly, intermittently, or not at all, airflow across the coil drops sharply and heat accumulates rapidly. Check that the fan blade spins freely, verify motor amperage draw, and listen for abnormal bearing noise.

  5. 05

    Faulty COND temperature sensor

    Part replacement

    If the sensor itself has drifted out of calibration or developed a fault, it may report falsely elevated temperatures even when the compressor is operating within normal thermal limits. This should be considered only after airflow, coil condition, refrigerant charge, and fan operation have been confirmed as normal.

See the test procedure for each cause

Frequently asked questions about P402

What does P402 mean on a Samsung air conditioner?
P402 means the condensate temperature sensor on the compressor has detected a temperature at or above 67°C, indicating the outdoor unit is overheating. The system is designed to tolerate this condition up to five times before initiating a full shutdown on the sixth detection. The code is a thermal protection response intended to prevent compressor damage. In most cases the cause is restricted airflow or a dirty condenser coil at the outdoor unit.
Can I fix P402 myself, or do I need a technician?
Some causes of P402 can be addressed without a technician, including clearing debris from around the outdoor unit, removing nearby obstructions, and rinsing a dirty condenser coil. If these steps do not resolve the issue, problems such as a refrigerant charge imbalance, a failing fan motor, or a defective sensor require professional tools and certification to diagnose and repair safely.
Is it safe to keep running my air conditioner when P402 appears?
No. P402 indicates that the compressor is being exposed to excessive heat, and continuing to operate the system under these conditions risks permanent compressor damage. The unit shuts itself down on the sixth detection specifically to prevent this outcome. The underlying cause should be identified and corrected before restarting the system.
Will resetting my Samsung air conditioner clear the P402 error?
A power cycle or reset may clear the active fault and allow the unit to restart, but it will not resolve the underlying cause. If the airflow restriction, coil fouling, or other contributing factor is still present, the condensate temperature will rise again and the system will eventually shut down again. Clearing the code without fixing the root cause risks accelerating compressor wear.
How much does it cost to repair a P402 error on a Samsung air conditioner?
Repair costs depend heavily on the root cause. A professional coil cleaning service typically ranges from around $75 to $200. Condenser fan motor replacement generally falls between $150 and $400 including parts and labor. Refrigerant diagnosis and recharge can range from $150 to $500 or more depending on refrigerant type and the amount required. Sensor replacement is usually one of the lower-cost repairs, often in the $100 to $250 range.

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